Process for the oxidation of olefins to unsaturated aldehydes and catalysts therefore

ABSTRACT

Catalysts are provided which are useful in the oxidation of olefins to aldehydes and conjugated dienes and in ammoxidation of olefins to nitriles. The catalysts comprise the combined oxides of uranium and arsenic on a catalyst support and the combined oxides of uranium and arsenic promoted by molybdenum, boron, vanadium, tin, nickel, bismuth, chromium, iron, manganese, zinc, tungsten, antimony, cerium, cobalt or rhenium.

United States Patent Grasselli et al.

[ Dec. 30, 1975 PROCESS FOR THE OXIDATION OF OLEFINS TO UNSATURATEDALDEI-IYDES AND CATALYSTS THEREFORE Inventors: Robert K. Grasselli,Chagrin Falls;

Maria S. Friedrich, Cleveland, both of Ohio The Standard Oil Company,Cleveland, Ohio Filed: Dec. 10, 1973 Appl. No.: 423,494

Related US. Application Data Division of Ser. No. 205,706, Dec. 7, 1971,which is a continuation-in-part of Ser. No. 16,984, March 5, 1970, Pat.No. 3,666,823, which is a continuation of Ser. No. 691,992, Dec. 20,1967, Pat. No. 3,544,616.

Assignee:

US. Cl 260/604 R; 260/465.3; 260/533 R; 260/598; 252/456; 252/457;252/458; 252/459; 260/666 A; 260/668 R; 260/668 D;

Int. Cl. C07c 45/04 Field of Search 260/604 R [56] References CitedUNITED STATES PATENTS 3,544,616 12/1970 Grasselli et al. 260/604 RFOREIGN PATENTS OR APPLICATIONS 1,808,990 7/1969 Germany 260/604 RPrimary ExaminerHoward T. Mars Assistant Examiner--R. H. Liles Attorney,Agent, or FirmHerbert D. Knudsen [57] 1 ABSTRACT 2 Claims, No DrawingsPROCESS FOR THE OXIDATION OF OLEFINS To UNSATURATED ALDEI-IYDES AND:CATALYSTS THEREFORE CROSS REFERENCE TO RELATED APPLICATIONS Thisapplication is a division of application Ser. No. 205,706 filed Dec.7,1971, which in turn is a continuation-in-part of application Ser. No.16,984 filed Mar. 5, 1970, now US. Pat. 3,666,823, which is acontinuation of Ser. No. 691,992 filed Dec. 20, 1967, now US. Pat. No.3,544,616.

BACKGROUND OF THE INVENTION This invention relates to oxidationcatalysts comprising oxides of uranium and arsenic optionallyincorporating promoters, which are useful for the catalytic oxidation ofolefins to aldehydes and conjugated dienes, and for the catalyticammoxidation of olefins to nitriles. The catalytic oxidation reactionsare exemplified by the oxidation of propylene to acrolein, the oxidationof isobutylene to methacrolein, the oxydehydrogenation of an olefinhaving 4 to 8 carbons, such as the oxydehydrogenation of butene-lorbutene-2to butadiene-1,3, the ammoxidation of propylene to acrylonitrileand the ammoxidation of isobutylene to methacrylonitrile.

The prior art is replete with a multiplicity of oxidation catalystsparticularly suited to the same reactions disclosed herein. Some ofthese oxidation catalysts are disclosed in US. Pat. Nos. 2,904,580;3,142,697; 3,179,694; 3,197,419; 3,198,750; 3,200,081; 3,200,084;3,226,421; 3,248,340; 3,264,225; 3,251,900; 3,257,474; 3,260,768; FrenchPat. Nos. 1,255,121,; 2,269,382; and British Pat. Nos. 864,666; 876,446;983,755. It is well-known that some catalysts are more successful thanothers and that the search for economically competitive catalystscontinues unremittingly. The oxidation catalyst of the instant inventionis a superior catalyst.

DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION The uraniumoxide-arsenic oxide base catalyst disclosed hereinis referred to as amixture of uranium and arsenic oxides, but this is not to be construedas meaning that the catalyst is composed either in whole or in part ofonly these compounds. The proportions of arsenic and uranium in thecatalyst system may vary widely. The preferred uraniumzarsenic atomicratio ranges from about 25:1 to about 1:6; Optimum activity appears tobe obtained at uraniumzarsenic atomic ratios within the range of fromabout 1:1 to about 1:4 and the catalyst is characterized by a negligibleloss of arsenic despite the relatively high reaction temperatures of thecatalytic processes in which it is useful.

The catalyst of the instant invention contains from to 95 percent byweight of a catalyst support, and preferably between 10 percent and 90percent. Any known catalyst support such'as alumina, pumice, silicon.carbide, titania, zirconia, alumina-silica, and the inorganicphosphates, silicates, aluminates, borates and carbonates stable underthe reaction conditions, may be used but silica is preferred.

In the preparation of the base catalyst useful in this invention, thearsenic oxide and uranium oxide can be 2 blended together or can beformed separately and then blended or formed separately, or together insitu.

The uranium oxide component of the instant catalyst can be useful in theform of uranous, uranic or combined uranous-uranic oxides, or byprecipitation in situ from a soluble uranyl salt, such as the nitrate,acetate, or a halide such as the chloride. Uranium metal can be used asa starting material, and if free arsenic is also employed, the arseniccan be converted to the oxide and the uranium to the nitratesimultaneously by oxidation in hot nitric acid. A slurry of hydrousarsenicarsenic oxide in nitric acid can be combined with a solution of auranium salt which is then precipitated in situ as the hydroxide bymaking the solution alkaline with ammonium hydroxide, the ammoniumnitrate and the other ammonium salts being removed by filtration of theresulting slurry or by thermal decomposition.

It will be apparent from the above that uranous and uranic bromides,chlorides, fluorides and iodides, nitrates, acetates, sulfites,sulfates, phosphates, thiocyanates, thiosulfates, oxalates, formates andhydroxides can be employed as the source of the uranium oxidecomponents. A preferred source is uranyl nitrate.

As starting materials for the arsenic oxide component there can be usedany arsenic Oxide such as arsenic trioxide or arsenic pentoxide; or ahydrolyzable or decomposable arsenic salt such as an arsenic halide.Arsenic metal can be employed, the oxide being formed by oxidizing themetal with an oxidizing acid, such as nitric acid. A preferred startingmaterial is ortho-arsenic acid.

The catalytic activity of the novel catalyst embodied in the presentinvention, is enhanced by heating the catalyst at an elevatedtemperature. Preferably, the catalyst mixture is dried and heated at atemperature of from 500F to 1500F, more preferably at about 700F to 900Ffor from 2 to 24 hours. If activity then is insufficient, the catalystcan be further heated at a temperature above about 1000F but below atemperature deleterious to the catalyst at which it is melted ordecomposed, preferably from about 1100F to about 1800F for from 1 to 48hours, in the presence of oxygen or an oxygen-containing gas such asair.

In general the higher the activation temperature, the less time requiredto effect activation. The sufficiency of activation at any given set ofconditions is ascertained by a spot test of a sample of the material forcatalytic activity. Activation is best carried out in an open chamber,permitting circulation of air or oxygen, so that any oxygen consumedwill be replaced.

The instant catalyst comprising the combined oxides of uranium andarsenic may be defined by the following empirical formula U As, 0, wherethe As:U atomic ratio is in the range from about 1:25 to about 10:1 andz is determined by the oxidation state of U and As in thecatalyst. It isconjectured that the combined oxides of the instant catalyst are presentas an activated catalytic Oxide complex.

Various metal oxides have been found to act as promoters in conjunctionwith the uranium-arsenic base catalyst, as for example, minor amounts ofan element or elements selected from Groups I-A, I-B, II-A, II-B, III-B,IV-A, lV-B, V-B, VI-B, VII-B, and VIII of the Periodic Table.Particularly effective promoters are the oxides of molybdenum, boron,vanadium, tin, nickel, bismuth, chromium, iron, manganese, zinc,antimony, cerium, and tungsten in an amount corresponding to 3 less'thanone atomic equivalent per atomic equivalent of either uranium orarsenic.

Promoter oxides may be incorporated into the base catalyst by blendinginto the gel before calcining, or by blending into the oven-dried basecatalyst before calc'ining. A preferred manner of incorporating promoterelements is by choosing a water-soluble salt of the promoter element,forming an aqueous solution of the salt, and-mixing this solution withuranyl nitrate and orthoarsenic acid solutions, and stirring whilecontinuously heating till the solution gels. The gel is then spoonedinto trays and oven-dried at 120C overnight. The dried catalyst is thencalcined starting at 800F, the temperature raised to 900F over a periodof 2 hours and the catalyst calcined overnight at this temperature. Afurther calcination at a higher temperature of at least 1000F for 3hours is generally employed to increase the activity of the catalystcomplex. This catalyst system is useful in the oxidation of olefins tooxygenated compounds, such as aldehydes and acids, in the presence ofoxygen; in the oxidation of olefins to unsaturated nitriles in thepresence of oxygen and ammonia; and in the oxydehydrogenation of olefinsto diolefins and aromatic compounds. Nitriles and oxygenated compoundssuch as aldehydes and acids can be produced simultaneously using processconditions within the overlapping ranges for these reactions as setforth in detail below. The relative proportions of each that areobtainable will depend on the process conditions, the particularcatalyst and on the olefin. The same catalyst may produce predominantlythe nitrile with propylene and predominantly the aldehyde and/or acidwith isobutylene. The term oxidationas used in this specification andclaims encompasses the oxidation to aldehydes and acids and to nitrilesand dienes all of which oxidation reactions require oxygen as areactant.

OXIDATION OF OLEFINS TO ALDEI-IYDES AND ACIDS The reactants used in theoxidation to oxygenated compounds are oxygen and an olefin having onlythree carbon atoms in a straight chain such as propylene or isobutyleneor mixtures thereof.

The olefins may be in admixture with paraffinic hydrocarbons, such asethane, propane, butane, and pentane; for example, a propylene-propanemixture may constitute the feed. This makes it possible to use ordinaryrefinery streams without special preparation.

The temperature at which this oxidation is conducted may varyconsiderably depending upon the catalyst, the particular olefin beingoxidized and the correlated conditions of the rate of throughput orcontact time and the ratio of olefin to oxygen. In general, whenoperating at pressures near atmospheric, i.e., 10 to 100 psig,temperatures in the range of 500F to 1100F may be advantageouslyemployed. However, the process may be conducted at other pressures, andin the case where superatmospheric pressures, e.g., above 100 psig, are

employed, somewhat lower temperatures are possible.

"In the case where this process is employed to convert propylene toacrolein, a temperature range of 750F to The apparent contact timeemployed in the process is not critical and it may be selected from abroad operable range which may vary from 0.1 to 50 seconds. The apparentcontact time may be defined as the length of time in seconds which theunit volume of gas measured under the conditions of reaction is incontact with the apparent unit volume of the catalyst. It may becalculated, for example, from the apparent volume of the catalyst bed,the average temperature and pressure of the reactor, and the flow ratesof the several components of the reaction mixture.

The optimum contact time will, of course, vary depending upon the olefinbeing treated, but in the case of propylene and isobutylene, thepreferred apparent contact time is 0.15 to 15 seconds.

A molar ratio of oxygen to olefin between about 0.5:1 to 5:1 generallygives the most satisfactory results. For the conversion of propylene toacroelin, a preferred ratio of oxygen to olefin is from about 1:1 toabout 2:1. The oxygen used in the process may be derived from anysource; however, air is the least expensive source of oxygen and ispreferred for that reason.

Water is formed as a product of reaction and it has been found that ithas a beneficial influence on the course of the reaction in that itimproves the conversion and the yields of the desired product. Sometimesit is desirable to add some water to the reaction mixture.

The manner in which water affects the reaction is not fully understoodbut the theory of this phenomenon is not deemed important in view of theexperimental results we have obtained.

Inert diluents, such as nitrogen and carbon dioxide, may be present inthe reaction mixture.

OXIDATION OF OLEFINS TO NITRILES The reactants are the same as thoseused in the oxidation of olefins to aldehydes described above exceptthat ammonia is included as a reactant. Any of the olefins describedabove can be used.

In its preferred aspect, the process comprises contacting a mixturecomprising propylene or isobutylene, ammonia and oxygen with either thepromoted or unpromoted catalyst of this invention at an elevatedtemperature and at atmospheric or near atmospheric pressure.

Any source of oxygen may be employed in this process. For economicreasons, however, it is preferred that air be employed as the source ofoxygen. From a purely technical viewpoint, relatively pure molecularoxygen will give equivalent results. The molar ratio of oxygen to theolefin in the feed to the reaction vessel should be in the range of0.5:1 to 4:1 and a ratio of about 1:1 to 3:1 is preferred.

Low molecular weight saturated hydrocarbons do not appear to influencethe reaction to an appreciable degree, and these materials can bepresent; consequently the addition of saturated hydrocarbons to the feedto the reaction is contemplated within the scope of this invention.Likewise, diluents, such as nitrogen and the oxides of carbon, may bepresent in the reaction mixture without deleterious effect.

The molar ratio of ammonia to olefin in the feed to the reactor may varybetween about 0.05:] to 5:1. There is no real upper limit for theammonia:olefin ratio, but there is generally no reason to exceed the 5:1ratio. At ammonia:olefin ratios appreciably less than the stoichiometricratio of 1:1, various amounts of oxygenated derivatives of the olefinwill be formed.

Significant amounts of unsaturated aldehydes, as well as nitriles, willbe obtained at ammoniazolefin ratios substantially below 1:1, i.e., inthe range of 0.15:1 to 0.7521. Outside the upper limit of this rangeonly insignificant amounts of aldehydes will be produced, and only verysmall amounts of nitriles will be produced at ammoniazolefin ratiosbelow the lower limit of this range. It is fortuitous that within theammoniazolefin range stated, maximum utilization of ammonia is obtainedand this is highly desirable. It is generally possible to recycle anyunreacted olefin and unconverted ammonia.

A particularly surprising aspect of this invention is the effect ofwater on the course of the reaction. We have found that in many caseswater in the mixture fed to the reaction vessel improves the selectivityof the reaction and the yield of nitrile. However, reactions notincluding water in the feed are not be be excluded from this inventioninasmuch as water is formed in the course of the reaction.

In general, the molar ratio of added water to olefin, when water isadded, is at least about 0.25:1. Ratios on the order of 1:1 to 3:1 areparticularly desirable, but higher ratios may be employed, i.e., up toabout :1.

The reaction is carried out at a temeprature within the range of fromabout 550F to 1100F. The preferred temperature range is from about 800Fto 1000F.

The pressure at which the reaction is conducted is also an importantvariable, and the reaction should be carried out at about atmospheric orslightly above atmospheric (2 to 3 atmospheres) pressure. In general,high pressures, i.e., about 250 psig, are not suitable, since higherpressures tend to favor the formation of undesirable by-products.

The apparent contact time is not critical, and contact times in therange of from 0.1 to about 50 seconds may be employed. The optimumcontact time will, of course, vary depending upon the olefin beingtreated, but in general, a contact time of from 1 to seconds ispreferred.

THE OXIDATIVE DEHYDROGENATION OF OLEFINS TO DIOLEFINS AND AROMATICS Inaccordance with the present invention, the promoted or unpromotedcatalyst system is employed in the catalytic oxidative dehydrogenationof olefins to diolefins and aromatic compounds. In the process, the feedstream in vapor form containing the olefin to be dehydrogenated andoxygen is conducted over the promoted catalyst at a comparatively lowtemperature to obtain the corresponding diolefin or aromatic compound.

By the term olefin as used herein is meant the open chain as well ascyclic olefins. The olefins dehydrogenated in accordance with thisinvention have at least four and up to about eight non-quaternary carbonatoms, of which at least four are arranged in series in a straight chainor ring. The olefins preferably are either normal straight chain ortertiary olefins. Both cis and trans isomers, where they exist, can bedehydrogenated.

Among the many olefinic compounds which can be dehydrogenated in thisway are butene-l; butene-2; pentene-l; pentene-2; heptene-l; octene-l;tertiary pentenes and hexenes having one tertiary carbon atom such asZ-methyI-pentene-l, 3-methyl-butene-l, 3,4-

dimethyl-pentene-l, 4-methyl-pentene-2; other branched chain olefinssuch as 2-methyl-butene-2, 2- methyl-butened, 3-methyl-pentene-2;cyclo-olefins such as cyclopentene; cyclohexene; 3-methyl cyclohexeneand cycloheptene.

Open chain olefins yield diolefins, and, in general, six-membered ringolefins yield aromatic ring compounds. The higher molecular weight openchain olefins may cyclize to aromatic ring compounds.

The feed stock in addition to the olefin and oxygen can contain one ormore paraffinic or naphthenic hydrocarbons having up to about 10 carbonatoms, which may be present as impurities in some petroleum hydrocarbonstocks and which may also be dehydrogenated in some cases. In thisoxidative dehydrogenation reac tion, propylene and isobutylene shouldnot be included in the feed in substantial amounts.

The amount of oxygen should be within the range of from about 0.3 toabout 3 moles per mole of olefin. Stoichiometrically, 0.5 to 1.5 molesof oxygen per mole of olefin is required for the dehydrogenation todiolefins and aromatics respectively. It is preferred to employ 'anexcess of oxygen, from 1 to about 2 moles per mole of olefin, in orderto ensure a higher yield of diolefin per pass. The oxygen can besupplied as pure or substantially pure oxygen or as air or in the formof hydrogen peroxide.

When pure oxygen is used, it may be desirable to incorporate a diluentin the mixture such as steam, carbon dioxide or nitrogen.

The feed stock is preferably catalytically dehydrogenated in thepresence of steam, but this is not essential. Usually, from about 0.1 toabout 6 moles of steam per mole of olefin reactant is employed, butamounts larger than this can be used.

The dehydrogenation proceeds at temperatures within the range of fromabout 325C to about [000C. Optimum yields are obtainable at temperatureswithin the range from about 400C to 550C. However, since the reaction isexothermic, temperatures in excess of 550C should not be used, unlessmeans are provided to carry off the heat liberated in the course of thereaction. Due to the exothermic nature of the reaction, the temperatureof the gaseous reaction mixture will be higher than the temperature ofthe feed entering the system by as much as C. The temperatures referredto are those of the entering gas feed near the reactor inlet.

The preferred reaction pressure is approximately atmospheric, within therange of from about 5 to about 75 psig. Higher pressures up to about 300psig can be used and have the advantage of simplifying the productrecovery.

Only a brief contact time with the catalyst is required for effectivedehydrogenation. The apparent contact time with the catalyst can varyfrom about 0.5 up to about 50 seconds but higher contact times can beused if desired. At these contact times, comparatively small reactorsand small amounts of catalyst can be used effectively.

in general, any apparatus of the type suitable for carrying outoxidation reactions in the vapor phase may be employed in the executionof these processes. The processes may be conducted either continuouslyor intermittently. The catalyst bed may be a fixed bed employing a largeparticulate or pelleted catalyst or, in the alternative, a so-calledfluidized" bed of catalyst may be employed.

The reactor may be brought to the reaction temperature before or afterthe introduction of the reaction feed mixture. However, in a large scaleoperation,is to preferred to carry out the process in a continuousmanner, and in such a system, the recirculation of the untreated olefinis contemplated.

The catalyst compositions and oxidation process of this invention arefurther illustrated in the following examples wherein the amounts of thevarious ingredients are expressed as parts by weight unless otherwisespecified.

EXAMPLES 1-16 1. In a typical preparation of the unpromoted catlyst.87.8 g of uranyl nitrate (U (NO .6H O were dissolved in about 100 cc ofhot water; 154.3 g of orthoarsenic acid H AsO H O were dissolved inabout 400 cc of hot water. The uranyl nitrate solution was added tothedilutc ortho-arsenic acid and the mixture stirred. To this mixturewas added 116.8 g of Ludox AS, a commerically available dispersion of 30percent by weight of silica, S The mixture was continuously heated withconstant stirring until it gelled. The gel was spooned into trays,placed in an atmospheric convection oven at 120C and dried overnight.The oven-dried catalyst was then heat-treated in a furnace open to theatmosphere, starting at 800F and being raised to 900F over a period ofabout two hours. The catalyst was calcined overnight at 900F. Thecatalyst obtained had a composition which may be written as 82.5 UAS O17.5% SiO:.

2. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1200F for 3.5 hours.

3. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1375F for 3 hours.

4. In another preparation of the unpromoted catalyst, 215 g of uranylnitrate were dissolved in about 200 cc of hot water; 64.6 g ofortho-arsenic acid H AsO H O were dissolved in about 100 cc of hotwater. The uranyl nitrate solution was added to the dilute orthoarsenicacid and the mixture stirred. To this mixture was added 1 16.8 g ofLudox AS a commercially available dispersion of 30 percent by weight ofsilica, SiO The mixture was continuously heated with constant stirringuntil it gelled. The gel was spooned into trays, placed in anatmospheric convection oven at 120C and dried overnight. The oven-driedcatalyst was then heat-treated in a furnace open to the atmosphere,starting at 800F and being raised to 900F over a period of about twohours. The catalyst was calcined overnight at 900F. The catalystobtained had a composition which may be written as 82.5% UASO5 5. 17.5%810..

5. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1200F for 3.5 hours.

6. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1500F for 3 hours.

7. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1700F for 3 hours.

8. In another preparation of the unpromoted catalyst 239 g of uranylnitrate (U0 (NO .61-l O were dissolved in about 200 cc of hot water;48.1 g of orthoarsenic acid H AsO H O were dissolved in about cc of hotwater. The uranyl nitrate solution was added to the dilute ortho-arsenicacid and the mixture stirred. To this mixture was added 116.8 g of LudoxAS, a commercially available dispersion of 30 percent by weight ofsilica, S10 The mixture was continuously heated with constant stirringuntil it gelled. The gel was spooned into trays, placed in anatmospheric convection oven at C and dried overnight. The oven-driedcatalyst was then heat-treated in a furnace open to the atmosphere,starting at 800F and being raised to 900F over a period of about 2hours. The catalyst was calcined overnight at 900F. The catalystobtained had a composition which may be written as 82.5% UAS O 17.5%SiO;.

9. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1200F for 3.25 hours.

10. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1500F for 3.5

hours.

11. A portion of the above-described catalyst (calcined at 900F) wasfurther calcined at 1750F for 3 hours.

Other catalyst compositions were prepared in a manner similar to thatdescribed hereinabove, so as to vary the ratio of arsenic to uranium.Ratios as low as 0.1 gave good conversions, though the betterconversions were obtained with ratios in excess of 2.

The following Table I shows runs for the conversion of propylene toacrylonitrile, made with each of the above-described unpromotedcatalysts, all the runs having been made under substantially similarprocess conditions, namely a weight hourly space velocity (WWH) in therange from about 0.04 to about 0.1 hrf, a reactor temperature in therange from about 850F to about 950F and a slight excess of ammonia overthe theoretical amount, at substantially atmospheric pressure.

TABLE 1 Percent Conversion to Acrylonitrile Moles AcrylonitrileRecovered Moles Propylene Fed Unpromoted Catalyst Calcined Over- PercentPer Pass TABLE I-continued Percent Conversion to Acrylonitrile RecoveredUnpromoted Catalyst Calcined Over- Moles Propylene Fed MolesAcrylonitrile Percent Per Pass Ex. Atomic Ratio night at 900F &Conversion of Propy- No ArseniczUranium Additionally for lene toAcrylonitrile 9 0.7 3.25 hrs. at l200F 28.4

10 0.7 3.5 hrs. at 1500F 23.1

11 0.7 3 hrs. at 1700F 11.5

14 3 3 hrs. at 1000F 57.2

15 3 3 hrs. at l200F 48.3

The following Table II shows runs for the conversion of isobutylene tomethacrylonitrile, made with some of and values for the symbols a, x andy are listed in the following Table Ill.

TABLE III Calcined Overnight at 900F Percent Per Pass,

Atomic Ratios Conversion of the above-described unpromoted catalysts,all the runs having been made under substantially similar processconditions as those described for preceding Table I.

TABLE II The following Table IV shows runs, for the conversion ofisobutylene to methacrylonitrile, make with some of the above-describedpromoted catalysts, all the Unpromoted Catalyst Calcined OvernightPercent Per Pass Con- Ex. Atomic Ratio at 900F and version isobutyleneN0 ArseniczUranium Additionally for to Methacrylonitrile 17 0.7 3 hrs.at 1500F 19.8 18 l 3.5 hrs. at l200F 39.7 19 2 3 hrs. at I700F 29.6 20 33 hrs. at l200F 42.8 21 5.8 3 hrs. at l375F 57.7

The following Table Ill shows runs, for the conversion of propylene toacrylonitrile, made with some of the above-described promoted catalysts,all the runs having been made under substantially similar processconditions as those described for preceding Table l. The promotedcatalyst composition may be written M runs having been made undersubstantially similar process conditions as those described for thepreceding Table l. The promoted catalyst composition may be written M, UAs 0 where M denotes the promoter element and values for the symbols a,x and y are listed in the following Table IV.

TABLE IV Calcined Overnight at 900F Percent Per Atomic Ratios PassConversion Ex. of Components and Additionally of Propylene No. Promotera x y for to Acrolein 33 Molybdel 1 0.25 3 hrs. at 1100F 56.1

num

34 Molybdel 1 0.25 3 hrs. at 1000F 66.8

num

35 Antimony l 1 3 9.4

36 Vanadium 0.1 l 3 8.3

U As 0 where M denotes the promoter element The following Table V showsruns, for the conversion of propylene to acrolein, made with some of theabovedescribed unpromoted and promoted catalysts, all the runs havingbeen made under substantially similar process conditions as thosedescribed for preceding Table I. The promoted catalyst composition M U,As where M denotes the promoter element and values for the symbols a, xand y are listed in the following Table V.

TABLE V l2 at a temperature within the range from about 500F to about 1100F a mixture ofa molecular oxygen-containing gas and either propyleneor isobutylene, or mixtures thereof, in a molar ratio of oxygen toolefin within the range from about 0.5:] to about 5:1, in the presenceof a supported catalyst composition of the empirical formula U As 0wherein x is a number within the range Calcined Over- Atomic Ratiosnight at 900F Percent Per Pass Conversion Ex. of Components andAdditionally of Propylene to No. Promoter a x y for Acrolein 37 None 10.7 3 hrs. at 1500F 9.0

38 None 1 4.5 3 hrs. at 900F 12.8

39 None 1 5.8 3 hrs. at 1000F 14.9

40 Molybde- 3 1 0.25 3 hrs. at 1100F. 50.2

num

41 Iron 0.1 1 3.0 3 hrs. at 1000F 28.4

42 Vanadium 1 1 3.0 3 hrs. at l200F 37.9

43 Bismuth 1 1 3.0 3 hrs. at 1000F 32.8

The following Table VI shows runs, for the conversion of isobutylene tomethacrolein, made with some of the above-described unpromoted andpromoted catalysts, all the runs having been made under substantiallysimilar process conditions as those described for preceding Table l. Thepromoted catalyst composition may be written M U As 0 where M denotesthe promoter element and values for the symbols a, x and y are listed inTable VI below.

TABLE VI from 1 to 25; y is a number within the range from 1 to 10; andz is a number taken to satisfy the oxidation state of the elements insaid catalyst composition.

2. The process for the oxidation of propylene and isobutylene to formacrolein and methacrolein, respectively, which comprises contacting in avapor phase at a temperature within the range from about 500F to about 1100F a mixture of a molecular oxygen-containing gas and either propyleneor isobutylene, or mixtures Calcined Over- Atomic Ratios night at 900FPercent Per Pass Conversion of Ex. of Components and Additionallyisobutylene to No. Promoter a x y for Methacrolein 44 None 1 0.7 3 hrs.at 900F 11.9 45 None 1 4.5 3 hrs. at I000F 14.7 46 None- 1 5 3 hrs. at1200F 18.8 47 Nickel 1 l 3 3 hrs. at I000F 31.9 48 Tin 0.5 1 3 3 hrs. at1100F 29.8 49 Molybde- 1 I 3 39.8

num

The following Table VI! shows runs, for the conversion of l-butene tobutadiene, made with some of the above-described promoted catalysts, allthe runs having been made under substantially similar process conditionsas those described under preceding Table l. The promoted catalystcomposition may be written M U As, 0 where M denotes the promoterelement and values for the symbols 0, x and y are listed in the TableVI! below.

TABLE V11 thereof, in a molar ratio of oxygen to olefin within the rangefrom about 0.5:1 to about 5:1,- in the presence of a supported catalystcomposition of the empirical formula M,, U As, 0, wherein a is a numberless than 1; x is a number from about 1 to about 25; y is a number fromabout 1 to about 10; and z is a number taken to satisfy the oxidationstate of the elements in the catalytic oxidation complex, where M is atleast one element selected from the group consisting of molybde-Calcined Over- Atomic Ratios night at 900F Percent Per 1. The processfor the oxidation of propylene and 5 num,boron, vanadium,tin,nickel,bismuth,chromium,

isobutylene to form acrolein and methacrolein, respectively, whichcomprises contacting in the vapor phase tungsten, antimony and cerium.

iron, manganese, zinc,

1. THE PROCESS FOR THE OXIDATION OF PROPYLENE AND ISOBUTYLENE TO FORMACROLEIN AND METHACROLEIN, RESPECTIVELY, WHICH COMPRISES CONTACTING INTH VAPOR PHASE AT A TEMPERATURE WITHIN THE RANGE FROM ABOUT 500*F TOABOUT 1100*F A MIXTURE OF A MOLECULAR OXYGEN-CONTAINING GAS AND EITHERPROPYLENE OR ISOBUTYLENE, OR MIXTURES THEREOF, IN A MOLAR RATIO OFOXYGEN TO OLEFIN WITHIN THE RANGE FROM ABOUT 0.5:1 TO ABOUT 5:1, IN THEPRESENCE OF A SUPPORTED CATALYST COMPOSITION OF THE EMPIRICAL FORMULA UXASY OZ WHEREIN X IS A NUMBER WITHIN THE RANGE FROM 1 TO 25; Y IS ANUMBER WITHIN THE RANGE FROM 1 TO 10; AND Z IS A NUMBER TAKEN TO SATISYTHE OXIDAION STATE OF THE ELEMENTS IN SAID CATALYST COMPOSITION.
 2. Theprocess for the oxidation of propylene and isobutylene to form acroleinand methacrolein, respectively, which comprises contacting in a vaporphase at a temperature within the range from about 500*F to about 1100*Fa mixture of a molecular oxygen-containing gas and either propylene orisobutylene, or mixtures thereof, in a molar ratio of oxygen to olefinwithin the range from about 0.5:1 to about 5:1, in the presence of asupported catalyst composition of the empirical formula Ma Ux Asy Ozwherein a is a number less than 1; x is a number from about 1 to about25; y is a number from about 1 to about 10; and z is a number taken tosatisfy the oxidation state of the elements in the catalytic oxidationcomplex, where M is at least one element selected from the groupconsisting of molybdenum, boron, vanadium, tin, nickel, bismuth,chromium, iron, manganese, zinc, tungsten, antimony and cerium.